Rubyzoisite

Rubyzoisite, also known as ruby in zoisite, is a natural gemstone comprising green zoisite with embedded red ruby crystals. The red crystals are corundum (ruby) colored by trace chromium, while the green matrix is zoisite colored by chromium as well. The result is a striking two-tone stone commonly found as mottled, patchy, or veined material.

The material is most closely associated with Tanzania, where rubyzoisite is quarried and marketed in cut and cabochon forms for jewelry and decorative pieces. It is valued for its contrasting colors and the unique patterns created by the ruby inclusions within the green zoisite.

In terms of physical properties, rubyzoisite is relatively soft for a gemstone, with a Mohs hardness around 6 to 7 due to the zoisite component, while the ruby crystals can be harder. This makes the stone more suitable for pendants and exhibit pieces than for everyday rings, and it benefits from careful setting to protect the softer matrix. The luster is typically vitreous to silky, and the stones range from opaque to translucent.

Typical uses include jewelry such as cabochons, beads, and decorative carvings. Care involves gentle cleaning with mild soap and warm water, avoiding ultrasonic cleaners and sudden temperature changes that can cause cracking or crazing in the matrix. While popular in crystal-enthusiast circles for its visual appeal, rubyzoisite is not a substitute for ruby in terms of hardness or value and is appreciated primarily as a distinctive ornamental gemstone.